Power Saving and Windows 8 Consumer Preview

I found my Windows 8 Consumer Preview crashed twice while listening to mp3 file.  The mp3 files was stored on a removable harddisk and it was playing directly from it using KMPlayer.  When the machine crashed, the screen was blank, and so it seemed to be like it's in power saving mode.  So I concluded that the problem handled when the machine kicked into power saving mode, and turned off  the feature that turned off screen after 10 minutes.  So far I haven't seen the crashing happened again.